#https://blog.csdn.net/qq_34489091/article/details/81073156
powershell -c "$n=1;$m=1;gc 'a.txt'|%%{$f=''+$m+'.txt';$_>>$f;if($n%%100000 -eq 0){$m++};$n++}" 

https://blog.csdn.net/weixin_33711647/article/details/93109901